A typical power cable includes one or more conductors in a cable core surrounded by one or more layers of polymeric material. Medium-voltage (6 to 36 kV), high-voltage (greater than 36 kV), and extra-high-voltage (greater than 220 kV) cables typically include a core surrounded by an inner semiconducting layer, followed by an insulating layer, and then an outer semiconducting layer, and an outermost layer (or sheath).
The load-carrying capacity of a cable system is limited, in part, by the heat transfer away from the conductor. Polyolefins, such as polyethylene, are frequently utilized in the insulating layer and/or in the semiconducting layer. Polyethylene has a low dielectric permittivity and a relatively high electrical breakdown strength.
Known are voltage-stabilizing agents for polyolefin compositions that increase electrical breakdown strength of insulating layers in power cable. Conventional voltage-stabilizing agents (such as the family of polycyclic aromatics, e.g. acenes), however, have poor compatibility with polyolefins. The art recognizes the continuous need for voltage-stabilizing agents compatible with polyolefins for (i) increased electrical breakdown strength of cable insulation material, (ii) increased reliability with existing cable designs and/or (iii) provision of high-stress designs that are able to deliver increased amounts of energy.